Fecal incontinence device, system and method

ABSTRACT

A device for treating fecal incontinence in a subject is provided. The device includes a plug configured for positioning mostly within an anal canal of the subject.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/546,879, filed Jul. 11, 2012, which is a continuation of U.S. patentapplication Ser. No. 12/376,294, filed Feb. 4, 2009, which is a §371(c)entry from PCT/IL2008/01450, filed on Nov. 5, 2008, which claimed thebenefit of U.S. Provisional Application Nos. 61/064,374 filed on Feb.29, 2008, and 60/996,275, filed on Nov. 8, 2007, the full disclosures ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to devices and methods suitable fortreating fecal incontinence.

Fecal incontinence (also referred to as anal or rectal incontinence oraccidental bowel leakage) is a disorder afflicting both children andadults with devastating social and psychological affects. It isestimated that in the United States alone more than 5.5 millionindividuals suffer from fecal incontinence and that the incidence rateof this disorder is 1-5%. Fecal incontinence is a major factor limitingthe rehabilitation of the elderly and disabled, preventing many of themfrom being cared for at home. Mild to moderate incontinence accounts forabout 80% of the market (gas, liquid and soiling) while severeincontinence accounts for the remaining 20%.

Fecal continence results from a coordinated motor function of analsphincters and pelvic floor muscles, the role of the rectum and sigmoidcolon as a fecal reservoir with capacitance and compliance and as apropulsive force with intrinsic motor activity, the effects of stoolconsistency, volume and delivery rate, the anorectal angle, andanorectal sensation.

The most common causes of fecal incontinence are structural orfunctional deficiencies of the sphincter muscles. Such deficiencies canresult from anatomic disruption of the sphincter mechanism which may becaused by obstetric injuries (perineal laceration and improperlyperformed median episiotomies), complications of hemorrhoid, fistula orfissure surgery (keyhole deformities), traumatic injuries (e.g.,impalement injuries), or cancer or from deterioration of the sphinctermuscles due to age, congenital disorders, systemic and metabolicdiseases, acquired neurological defects, and diseases of the colon andrectum.

Anal sphincters are muscular structures that assist in controlling theflow of feces and release of flatus from the colon. The internal analsphincter (IAS) and the external anal sphincter (EAS) encircle the analcanal and form a part of the anorectal ring (see FIG. 1). The IAS is athickening of the gastrointestinal smooth muscle; it maintainscontinence at rest. The EAS is composed of striated, voluntary muscle.The EAS, the puborectalis, and the levator ani muscles work in concertto prevent leakage of flatus and feces when there is an increase inabdominal pressure or when the internal anal sphincter relaxes afterrectal distention.

Resting pressure in the anal canal is typically 60 mm Hg (1.1 psi),increasing up to 100 mm HG (1.9 psi) in strain or forced exertion. In anormal individual (normal parameters vary widely), the myogenic activityof the involuntary internal sphincter contributes about 10% of the analresting pressure, and 45% is due to the sympathetic innervation of theinternal sphincter, for a total of 55%. The remainder of the restingtone is from the hemorrhoidal plexus (15%) and the external analsphincter (30%). The external sphincter supplies 100% of the voluntaryshort-term squeeze pressure. Therefore, what is needed to improvecontinence is a technology that can influence the ability of the anus toseal better in the resting state while not interfering with thedistention function of the sphincter during defecation.

Present treatment approaches for restoring fecal continence includenon-surgical and surgical therapy. Non-surgical therapy for incontinenceinclude biofeedback and perineal strengthening exercises beneficial inalleviating symptoms of seepage and occasional loss of control andelectrical stimulation to improve contraction of the sphincter muscles.

Surgical therapy approaches include implantation of artificial valves(see, for example, U.S. Pat. Nos. 6,471,635, 6,749,556, and U.S. patentapplication Ser. Nos. 10/269,949 and 10/651,851), injection of bulkingagents into the anal mucosa or the anal sphincters (see, for example,Vaizey and Kamm, British Journal of Surgery 2005; 92: 521-527),implanted electrodes for stimulating the pudendal or sacral nerves (see,for example, U.S. Pat. Nos. 6,907,293 and 7,054,689) or sphinctericmuscles (see, for example, PCT publication No. WO06047833).

Fecal incontinence can also be partially controlled using absorbentpads, absorbent plugs or hard plugs/valves and the like, however, suchapproaches are not well tolerated by individuals due to efficacy,convenience and comfort limitations as well as sealing limitations.

Thus, there remains a need for a device and method for treating fecalincontinence which are devoid of the above limitations.

BRIEF DESCRIPTION OF DRAWINGS

The invention is herein described, by way of example only, withreference to the accompanying drawings. With specific reference now tothe drawings in detail, it is stressed that the particulars shown are byway of example and for purposes of illustrative discussion of thepreferred embodiments of the present invention only, and are presentedin the cause of providing what is believed to be the most useful andreadily understood description of the principles and conceptual aspectsof the invention. In this regard, no attempt is made to show structuraldetails of the invention in more detail than is necessary for afundamental understanding of the invention, the description taken withthe drawings making apparent to those skilled in the art how the severalforms of the invention may be embodied in practice.

In the drawings:

FIG. 1 is an illustration of the anatomy of the anal canal andassociated tissues.

FIG. 2 illustrates the position of an in-situ formed vinyl polysiloxane(VPS) plug within an anal canal and rectum.

FIG. 3 illustrates a fecal incontinence plug and applicator constructedin accordance with the teachings of the preset invention compared withan image of in-situ fanned VPS plugs.

FIGS. 4A-C illustrate delivery and positioning of the fecal incontinenceplug of the present invention.

FIGS. 5A-C illustrate an alternative embodiment of a fecal incontinenceplug and applicator constructed in accordance with the teachings of oneembodiment of the present invention.

FIG. 6A illustrates an in-situ formed VPS plug superimposed over asagittal plane view of the anal canal (left) and a negative mold of thein-situ need plug (right).

FIG. 6B illustrates one embodiment of the fecal incontinence system ofthe present invention (left) along with the positioning and fit of theplug in cross section within the anal canal as is demonstrated via useof a molded model of the anal canal from an incontinent patient (right).

FIG. 7 is a cross sectional view showing specific features of the plugof the present invention.

FIGS. 8A-C illustrate steps in administering the fecal incontinence plugof the present invention using a finger-operated applicator superimposedon an illustration of an anal canal showing plug positioning during eachstep of the administration procedure.

FIGS. 9A-B illustrate one configuration of the present plug which isintroduced into the anal canal without an applicator as an elongatedsolid body. The plug core material melts at body temperature allowingthe plug to resume its relaxed liquid-filled configuration. The plug isillustrated in its solid core (FIG. 9A) and liquid core (FIG. 9B)configurations.

FIGS. 10A-B illustrate incontinence diapers of an incontinent subjectprior to (FIG. 10A) and during (FIG. 10B) use of the present plug. Oneor more incontinence diapers were collected for each day of the testingperiod.

DETAILED DESCRIPTION

The present invention is of devices, systems and methods which can beused to treat incontinent passageways. Specifically, the presentinvention provides a novel passageway plugging approach which can beused to treat fecal incontinence.

The principles and operation of the present invention may be betterunderstood with reference to the drawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangement of the components setforth in the following description or illustrated in the drawings. Theinvention is capable of other embodiments or of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting.

Fecal incontinence is a socially devastating disorder which affects atleast 2.2 percent of community dwelling adults and 45 percent of nursinghome residents. People who have fecal incontinence may feel ashamed,embarrassed, or humiliated; some don't want to leave the house out offear they might have an accident in public. Treatment of fecalincontinence depends on the cause and severity of the disorder.

Severe cases are typically treated by surgeries for repairing damagedsphincters, reinforcing anorectal structures, implanting artificialsphincters, and transferring muscle tissue. Mild to moderate cases offecal incontinence are typically treated using special diets,medication, bowel training, or diapers. Although the latter approachescan reduce fecal discharge or help contain fecal discharge in somepatients, they are either ineffective or are unacceptable for manypatients.

Thus, despite the availability of pharmacological, behavioral andsurgical treatments for fecal incontinence, many patients remainsymptomatic.

To overcome the deficiencies of diapers and yet provide an easynon-surgical solution to this problem, use of anal plugs has beensuggested. Such plugs are typically preformed from hard polymers or softabsorbent materials. The plug is introduced by the patient through theanal canal and into the rectum and much like a tampon is designed tocontain or block any discharge.

Although such plugs have been proven somewhat effective in containingsolid fecal discharges they are not efficient in containing liquiddischarge and in addition are not well tolerated by patients (see,Deutekom and Dobben, “Plugs for containing faecal incontinence” 2007 TheCochrane Collaboration. Published by John Wiley & Sons, Ltd).

The present inventors have postulated that a plug devised forpositioning mostly within the anal canal while being capable ofmaintaining the anal canal free of fecal solids or liquids would beadvantageous over prior art rectal plugs since the anal canal is lesssensitive than rectal tissues. In addition, in contrast to the teachingsof the prior art, the present inventors further believe that due to thedynamic nature of the rectum walls opening up laterally during filling[McMahon et al. Neurogastroenterol. Motil. (2005) 17, 531-540], plugsthat attempt to seal against the side walls of the rectum with sponge orballoon type plugs are prone to leakage as the rectum walls invariablepull away from the sealing surface as the rectum fills with fecalmatter. To produce sufficient force on the rectal walls to enablesealing, prior art plugs have to be at least 30 mm in diameter and as aresult, such plugs are difficult to pass, and are intolerable due to thepressure on the rectal walls being felt by the patient as an urge toevacuate. On the other hand, the plug of the present invention sealsagainst the relatively stable geometry of the bottom neck portion of therectum and/or the side walls of the anal canal, and as such exhibitssuperior sealing capabilities. Furthermore, physical pressure on theside rectal walls or occupying more than a few cubic centimeters in therectum causes unpleasant sensations and a desire to defecate, whereas aplug made of soft material seated at the bottom region of the rectum andin the anal canal is essentially imperceptible. As an analogy, prior artplugs attempt to seal against the walls of the bathtub whereas the plugof the present invention seals downwards on the drain directly.

In order to design a plug capable of anchoring and sealing at the analcanal, the present inventors formed impressions of the anal canals andlower rectums of both continent and incontinent human subjects using aninjectable vinyl polysiloxane (VPS) impression material. VPS materialwas introduced into the rectum and anal canal as a liquid andpolymerized in situ into a plug that blocked the anal canal with ahighly ridged and thin “stem” and formed a small “cap” in the lowerrectum (see FIG. 2), effectively restoring continence to severelyincontinent patients. The plugs were evacuated on their own along withfecal matter during the next voluntary bowel movement. Observations madeon evacuated plugs led the present inventors to notice that upondefecation, fecal matter was impacted along the top and side surface ofthe cap, but no fecal matter touched the lower neck surface of the capor the stem that was present in the anal canal. These unexpectedfindings indicated that the sealing occurs not against the lateralrectal walls, but rather along the bottom portion of the rectal neckwhere it transitions into the anal canal, and in the anal canal itself.

The shapes of the expelled plugs demonstrated that anal canal walls arehighly folded (FIGS. 2 and 6A) thus suggesting that a plug designcapable of effectively anchoring and sealing in the anal canal mustconform to the anatomy of the canal walls. The VPS plug molded itselfperfectly within the complex and unique geometry of each patient's analcanal and rectum and could not be felt by patients due to the fact thatit did not stretch or deform the rectum or anal canal. Unexpectedly,there were just a few differences in the macroscopic shapes of theexpelled VPS plugs between continent and incontinent patients. VPS plug20 in FIG. 3 was formed in a normal subject whereas VPS plug 30 in FIG.3 was formed in a severely incontinent subject. All plugs showed anapproximately 60 degree widening of the neck of the lower rectum with anelliptical cross section as viewed in a transverse section of the capthat fits within a rectangle of approximately 20 mm.times.10 mm at aheight of approximately 15 mm above the top of the anal canal. As seenin FIG. 3, the key differences in the plugs between normal subjects andthose suffering from fecal incontinence are: [0035] i. The stem regionsof VPS plugs right below the cap portion of subjects with fecalincontinence had greater cross sectional area (approximately 10-40mm.sup.2) than the stem region of normal subjects (approximately 1-2mm.sup.2). This implies that there was less resting pressure in the analcanal to push away the liquid VPS before it polymerized. The polymerizedVPS stem formed a perfectly anatomical internal mandrel against whichthe anal canal could seal even without significant resting pressure, andtherefore the VPS plugs dramatically improved the continence of these FIsubjects. In normal subjects, the area at the top of the VPS stem waspaper thin, indicating the proper functioning of a high pressure zone inthe anal canal where the primary sealing occurs. It is thereforehypothesized that a major design parameter of pre-formed plugs of thepresent invention that will allow for a limited range of pre-sized plugsto work for patients suffering from light to severe fecal incontinencewill be the shape, size and mechanical properties of this part of thestem. [0036] ii. The angle of the rectum versus the anal canal is highlycurved backwards in continent subjects and less so in incontinentsubjects. [0037] iii. The length of the anal canal is somewhat longer incontinent subjects than in incontinent subjects.

As is further described hereinunder, the present inventors generatedseveral plug designs which incorporate features derived from the VPSplugs and are important for both sealing and anchoring the plug in theanal canal. While testing these plugs it was further uncovered that byusing an ultra-soft and elastic form-fitting plug body, a singleuniversal plug design in a few pre-set sizes can fit most if not allincontinent patients, including smaller sizes for pediatric patients.

Thus, according to one aspect of the present invention there is provideda plug useful in preventing unwanted discharge of fecal fluids orsolids. Such a plug can be used by subjects suffering from incontinencecaused by neural damage, muscle damage or both, or by subjects sufferingfrom incontinence caused by an irritable bowel (e.g. inflammatory boweldisease, irritable bowel syndrome, ulcerative colitis, Crohns diseaseand the like).

The plug of the present invention is constructed capable of:

(i) residing primarily in the anal canal with a small top portion beingin the lower rectum region and optionally a small bottom portionresiding outside the rectum against external tissues and elasticallyconnected to the top portion;

(ii) sized and shaped to fit the natural anatomy of the anal canaland/or the lower rectum;

(iii) being of sufficiently soft and elastic material or covered by orfilled with a soft material such that it is essentially imperceptibleand conforms to the anatomy of the anal canal and lower rectum, evenduring movement;

(iv) optionally include an invaginatable, flowable or moldable surfacethat conforms precisely to the surface morphology of the walls of theanal canal and lower rectum for improved sealing and anchoring; and

(v) being elastically stretchable in order to fit various anal canallengths and to provide an elastic biasing force to help in anchoring andsealing Such features ensure that the plug effectively seals and anchorsalong the length of the anal canal and in the lower rectum therebyproviding cooperative anchoring and sealing. In addition, the fact thatplug conforms to the anatomy of the anal canal and lower rectum enablesit to stay in place and seal without applying any perceptible pressureon the walls of the anal canal and/or rectum even as the rectum anatomychanges as the rectum fills with fecal matter.

Furthermore, since the plug body resides below the side walls of therectum, it does not trigger sensory receptors present in rectal tissueand thus does not cause discomfort like prior art plugs as describedabove.

Thus, such a preformed plug would function similarly to the in-situformed plug shown in FIG. 2.

FIG. 3 illustrates plugs 20 and 30 which are VPS impressions from anormal and a severely incontinent human subject respectively. FIG. 3also shows one embodiment of the fecal incontinence plug of the presentinvention which is referred to herein as plug 10. Plug 10 is shownapplied onto applicator 50 (which is further described hereinbelow).

Plug 10 of the present invention is designed such that it is capable ofspanning the anal canal from the external anal orifice to the lowerrectum. Sealing is primarily provided in the lower rectum and upper analcanal regions where the anal canal transitions through a narrow neckregion into rectal tissue.

It is well known that once the anal canal is exposed to fecal matterthat escapes downward from the rectum, a positive feedback is initiatedthat relaxes the internal anal sphincter and causes an uncontrolled andimmediate urge to defecate. It is hypothesized that by preventing fecalmatter from reaching the anal canal in the first place, the chemicaland/or mechanical sensors that trigger the sphincters to relax and thereflex to defecate are not activated and therefore the involuntary urgeto defecate is reduced in at least some of the incontinent patients. Inthis scenario, the body's natural sphincter mechanism and the plug'sminimal sealing of the lower rectum and upper anal canal regions augmenteach other and work cooperatively to prevent leakage of fecal contentsinto the anal canal and hence restore continence. In contrast, prior artplugs don't augment the body's natural sealing mechanisms, but rathertry to block the passage of fecal contents mainly with their bulk, sizeor absorption capabilities.

In order to accomplish the functionality described above, the fecalincontinence plug of the present invention is preferably characterizedby several distinct features. It includes an elongated body (alsoreferred to hereinbelow as stem portion 12) which at least some portionof which is preferably capable of elastically stretching to accommodateseveral lengths of anal canals (and thus fit different individuals) andalso to allow overshoot of anchoring element (also referred tohereinbelow as cap portion 14) high into the rectum so that cap portion14 which is introduced into the anal canal concave down due to dragforces during insertion seats in the lower rectum concave up duringapplicator 50 withdrawal.

With reference to FIGS. 6B-9, plug 10 includes at least one, preferablytwo protrusions, one at each end of the elongated body; the firstprotrusion (also referred to hereinbelow as anchoring element or capportion 14) mainly functions in sealing while also providing someanchoring, whereas the second protrusion (also referred to hereinbelowas biasing cap or biasing element 21) functions in maintaining the plugwithin the anal canal (by providing a force countering upward movementof plug 10 in the neck portion of the rectum). The embodiments of thepresent plug described hereinbelow provide more detail as to specificplug portions and their function. It will be appreciated that althoughsuch embodiments are presently preferred, alternative plugconfigurations, including, for example, configurations having adiaphragm with an elastic rim or a hollow windsock or inverted conicalcondom shape with the open end in the lower rectum with a stiffeningring keeping the open end pressed against the lower rectum and thewindsock body or condom sheath resting in the anal canal where the fecalcontents themselves fill the windsock or sheath and form the plug arealso envisaged herein. Such configurations can be implemented with orwithout biasing element 21 to keep the plug in place.

As is shown in FIG. 3, one embodiment of plug 10 includes a stem portion12 which is attached to or contiguous (co-formed) with an anchoringportion (also referred to herein as cap portion 14); forming a structuresimilar to a golf tee or to the in-situ molded VPS plugs shown in FIGS.2 and 3.

Stem portion 12 can be a substantially cylindrical rod with a lengthranging from 0.5 to 6 cm and a diameter of 0.1 to 1 cm. The stem can begrooved, ridged, textured, or composed of stacked discs or many smallerparallel filaments (round or hexagonal tassel-like filaments that canrearrange dynamically to fill any shaped cross section) to increasesurface area or to better conform to the natural folds in the analcanal. The ridges can be designed such that the mucosal surfaces formaround them and therefore improve the seal of plug 10. As shown in FIG.5A, at the top of stem portion 12, there can be a stem upper region 13with different geometrical, physical, mechanical or chemical propertiesgiven that this is hypothesized to be a primary region of sealing thatneeds reinforcement in fecal incontinence patients. Stem upper region 13is intended to sit in proximity to the primary sealing region of theanal canal, which is towards its top based on the experimental resultsof the present inventors with the VPS plugs. For example, stem upperregion 13 can be a harder material, or a fluid, gel, gas or particlefilled balloon that applies gentle pressure against the anal canal withdynamic geometry and uniform pressure distribution. Uniform pressuredistribution is important in the anal canal as this region is in contactwith the internal hemorrhoids which are pressure and abrasion sensitive.

Stem portion 12 can be fully in the anal canal with no part of itexposed, or can extend below the anal canal and a portion exposedbetween the patient's legs, allowing the patient to pull stem portion 12and seat cap portion 14 against the lower rectum or remove plug 10altogether from the rectum. Cap portion 14 is designed to apply pressureto the lower rectum in the direction of fecal flow. As such cap portiondoes not apply any substantial radial forces to the rectal walls; infact the preferred configuration of cap portion 14 is a flat orbowl-shaped disc which is designed to seat on top of the lower rectum atthe point where it narrows and transitions into the anal canal and actin a manner similar to a drain plug. As such, anchoring of cap portion14 results from forces applied largely to a bottom surface of capportion 14 and not on the periphery thereof.

Stem portion 12 can include within it or be comprised of a non-elasticdrawstring that is over-molded by cap portion 14 and perhaps also partsof stem portion 12 itself. Preferably, at least some part of stemportion 12 is axially flimsy and radially elastic to enable it toconform the various and dynamic curvatures of the anal canal asexplained more fully below.

Stem portion 12 can also include a biasing element 21 (also referred toherein as biasing cap 21) attached opposite cap portion 14 (see FIGS. 6Band 7 for example). FIG. 6A shows VPS plug 30 superimposed against anillustration of the anal anatomy, along with negative mold 32 of VPSplug 30 which represents the actual rectal and anal anatomy of thepatient. On the right side of FIG. 6B, a cut-away plug 10 is insertedinto negative mold 32 to demonstrate the fit of plug 10 into the naturalgeometry of the lower rectum and anal canal. Biasing cap 21 functions insecuring plug 10 within the anal canal and preventing plug 10 fromriding up into the rectum due to displacement by fecal matter or due tocontractions of the rectum against a wedge-shaped cap portion 14 whichgenerates an upward force. As such, when plug is positioned within theanal canal (using the steps shown in FIGS. 8A-C) and cap portion 14anchored in the lower rectum, biasing cap 21, which resides outside theanal canal (against the skin external to and surrounding the anus, seeFIG. 6B) applies a gentle pulling force on stem portion 12 therebycausing slight stretching and adjustment of the length of stem portion12 to correspond to the length of the anal canal. Following positioning,biasing cap 21 resides against the external surface of the anuseffectively providing a counter force of 100 grams or less to theanchoring of cap portion 14. Such a biasing force is distributed over afew square centimeters of soft material of biasing cap 21 and hence is avery gentle and effectively imperceptible counter force which can betolerated for many hours or even days without discomfort as demonstratedin the examples below.

As the anal canal does not like to be occupied and tends to push out anyforeign objects within it, plug 10 would tend to be pushed up into therectum without biasing cap 21 therefore compromising the seal of capportion 14 against the lower rectum. Likewise, plug 10 would tend to bepushed outward and out of the body and end up between the patient's legswithout the anchoring of cap portion 14. The balance of forces betweencap portion 14 and biasing cap 21 through an elastic element allows forstable and self-contained positioning of plug 10 in the anal canal atall times, without the need for user adjustment or intervention,external tubes, tape, string or other anchoring schemes which may causediscomfort.

Cap portion 14 and biasing cap 21 can each be independently shaped as,for example, an inverted cone with the tip contiguous with stem portion12, as a diamond-profiled head with conical surfaces on the top andbottom, as a spherical or conical balloon (which can be fully orpartially filled with fluid, gas, particles or a gel), a skirted balloonor a balloon connected to a disk, bowl or rim element that deforms toseal the lower rectum, a ring, or as a cupped or flat disc or set ofdisks with a circular or elliptical transverse cross section. Capportion 14 can also be a random collection of squishy “tentacle-like”filaments that collapse together to form a physical obstruction to thepassage of fecal matter through the anal canal. As shown in FIG. 5A, capportion 14 can have a fixed, detachable or dissolvable nose cone 16 ontop to facilitate easier entry into the anal canal.

In the preferred configuration, cap portion 14 is a flexible flat disc.Such a configuration minimizes radial contact between cap portion 14 andthe rectal walls and enables cap portion to conform to the subjectsanatomy and provide an efficient and adaptable seal.

As shown in FIG. 5A, cap portion 14 or a portion thereof can be a disk15 with thickness of 10-3000 microns, with or without stiffening andshaping rings, ridges or ribs. Disk 15 can be elastically folded forwardand retained in this position to form nose cone 16 and then releasedwhen in the rectum to create a barrier element. If unrestrained, disk 15folds backwards into the anal canal during insertion and upon withdrawalof the applicator, disk 15 folds forward and seats in the lower rectumto provide additional sealing and anchoring capabilities to plug 10. Capportion 14 can take the form of an inverted umbrella biased open by itsnatural relaxed state, elastic ribs or via a mechanism activated throughthe applicator. Cap portion 14 can be made of two or more elements, forexample as a balloon for anchoring and flat or pleated skirt for sealingor a series of discs of variable diameter arranged one on top of theother (see FIG. 6B for example). The diameter of cap portion 14 canrange between 0.5 to 5 cm. Cap portion 14 can have sufficient size andrigidity so as to not migrate downward into the anal canal, but still besmall enough to not be felt and to be evacuated easily. The less massthere is in the upper cap portion 14, the less likely it is that therectum will have something to push against when trying to void plug 10out of the body. A cross sectional area in the range of 0.5-5 sq cmshould be sufficient for anchoring yet not be felt nor be so bulky as toprovide mass against which the rectum can push to void it until a fulldefecation is underway. The overall volume of plug 10 can range between0.5 to 10 ml, preferably 1-3 ml.

Plug 10 can be constructed as a hollow or solid structure or acombination of hollow and solid portions. For example, stem portion 12can be constructed as a hollow or solid rod while cap portion 14 can befabricated as a solid cone or disc or as a hollow sphere or vice versa.Any hollow spaces can be filled with a internal sleeve, liquid, gel,gas, foam or solid particles.

Biasing cap 21 is constructed so as to provide external anchoring whichmaintains a slight pulling force on cap portion 14. In addition, sincebiasing cap 21 resides outside the anus and against external tissues ofthe subject, it should be configured for maintaining tissue contactwhile providing the necessary (although minimal) restraining force oncap portion 14 and enough surface area such that it is not pulled intothe anal canal and distributes the restraining force over sufficienttissue area to prevent discomfort (for example a downward-facingbowl-shaped disk .about.2.5 cm in diameter, 1 mm thick, made of shore A3 silicone). Thus, biasing cap 21 can be fabricated from soft thinmaterial as a flat, yet foldable sheet which can be, for example,disc-shaped. A preferred configuration of cap portion 14 and biasing cap21 is shown in FIG. 7. Since biasing cap counters an anchoring forceapplied by cap portion 14, it does not need to be attached via adhesiveor other means to external tissues of the subject in order to maintainplug 10 in position, but merely needs to be in biasing contact withexternal tissue (e.g. tissue surrounding external surface of analorifice.

Plug 10 does not need to appreciably change in volume, girth or shapefollowing introduction thereof into the anal canal in order tofacilitate anchoring and/or sealing.

Thus, anchoring of plug 10 within the anal canal and rectum does notrequire uptake of fluids by portions thereof residing within the analcanal/rectum (i.e. cap portion and stem) and does not require activationor any shape change (e.g. as facilitated via inflation). As such, plug10 can be constructed from non-porous, non-absorbent material which isnot structurally modified following insertion. This is in contrast toprior art plugs which typically anchor within the rectum via a 2-3 foldexpansion in volume (via fluid uptake, relaxation of compressed shape,or inflation). This feature of plug 10 of the present invention ensuresthat it does not exert any appreciable radial pressure on the walls ofthe rectum or anal canal and as such does not cause sensation ordiscomfort when in use. Since plug 10 does not exert any significantforces on the tissue lining the anal canal and rectum it can be utilizedover extended time periods (days). Prior art devices such as the ProCon2 are typically limited to 8 hour use periods since extended use canlead to capillary blood flow blocking and tissue necrosis.

Furthermore, the small size of Plug 10 ensures that it can be evacuatednaturally without user intervention or discomfort as is it smaller indiameter than feces, whereas the prior art plugs need to be deflated orpulled out at a size larger than the relaxed anal canal, causingsignificant discomfort and inconvenience. Plug 10 is configured so thatit in its sealing-capable configuration (i.e. no further change ofvolume needs to occur to effect sealing) plug 10 can be elasticallydeformed to enable easy entry and exit through an opening 2.5 cm indiameter or smaller.

As is mentioned hereinabove, plug 10 relies on anchoring at the stemand/or cap portions. When anchored at both the stem and cap portions,cooperative anchoring is achieved by the combination of two separateanchoring mechanisms, a downward force biasing cap portion 14 againstthe neck-like structure above the anal canal and an adherence/frictionalforce between stem portion 12 (and optionally cap portion 14) and thesurface of the anal canal wall in which stem portion 12 resides.Additionally, cap portion 14 can be designed that fecal matter andliquids accumulating on top of cap portion 14 serve to better anchorplug 10 in place by applying a downward force thereupon, and thereforealso improve the seal against the lower rectum. This is in contrast toprior art plugs that seal against the sides of the rectum. Since withsuch plugs the filling of the rectum by fecal matter moves the tissueaway from the sealing surface and weakens the sealing and anchoring byallowing fecal matter to flow around the prior art plug thus allowingfecal matter to enter the top of the anal canal and cause an urge todefecate.

The anchoring schemes described herein ensure that plug 10 remainssecured in place and enables compensation for temporary loss ofanchoring (e.g. during anal canal movement). Human subjects that haveused both the VPS plugs and plug 10 of the current invention report noproblem in passing gas around the plug. Neither the VPS plug nor plug 10of the current invention are permeable to gas. Therefore, it gas escapesaround plug 10 by temporarily detaching a region of cap portion 14 fromthe tissue, but since plug 10 is also anchored at stem portion 12 and atother regions of cap portion 14, such escaped gas will simply travel asa wave along the outside surface of plug 10 and not completely dislodgeplug 10 from its position.

In a further embodiment of the present invention, gas release channelsor valves can be built in to plug 10 to enable gas to pass through plug10, to further facilitate passing of gas. Such channel can open underpreset pressure differentials, and be open channels or protected withgas-permeable/water-impermeable filters such as hydrophobic foams. Theinner lumen of stem portion 12 can form such a conduit or channel.

An additional advantage to the anchoring scheme of the present inventionis the ease of evacuation the plug upon defecation. Most prior art plugsrequire a removal mechanism (e.g. deflation of a balloon or pulling on adraw string) in order to facilitate removal of the plug. As is mentionedabove, such a mechanism is necessary in prior art plugs since theirrectal positioning and anchoring scheme (via radial expansion) impliesthat they are substantially larger than a relaxed anal canal (3-6 cmdiameter) and thus are difficult to pass.

Since plug 10 of the present invention does not rely on a radial forceor a large diameter anchor for anchoring, the act of voluntarydefecation naturally dilates the anal canal, thereby detaching the topanchoring of plug 10 and enabling effortless evacuation thereof alongwith the fecal matter. It has been demonstrated in incontinent patientswith the VPS plugs described herein as well as patients with plug 10that even in cases where there was no voluntary control of defecationdue to severe neurological deficits, the use of a plug of which issimilar in size and shape to the plug of the present invention preventedcontinuous leakage of fecal contents, thereby allowing sufficient fecalmatter to accumulate in the rectum to restore the natural feedback tohave regular bowel movements. The use of plug 10 of the presentinvention enabled these patients to defecate on a regular schedule withno leakage in between bowel movements, thereby restoring control oftheir defecation behavior.

Cap portion 14 is preferably configured to facilitate insertion into theanal canal, it may also coated with a lubricant on its upper surface.Such a lubricant can be present in grooves, ridges or dimples on the topportion of cap portion 14, or applied thereto just before use andrestrained from dripping off plug 10 by the surface features above, orby a circumferential dam. The packaging protecting plug 10 can also havea form-fitting inner face that retains a layer of the lubricant on thetop portion of cap portion 14. Alternatively, a peel off protectivelayer can protect the lubricant and be removed by the user just prior touse. Appropriate personal lubricants are well known in the art, beingpre-applied to enema tips for example.

Stem portion 12 can include an insert for stiffening stem portion. Suchan insert (23 in FIGS. 6B and 7) can be used to stiffen stem portion 12thus facilitating insertion of plug 10, as well as acting as aprotective sheath for an in-plug applicator (further describedhereinbelow with respect to applicator designs) thereby minimizing thechances that such an applicator perforates stem portion 12 or capportion 14. Insert 23 can be longer than stem portion 12 (see FIG. 6B)and therefore extend outside the anus and serve as a handle anddrawstring for manual removal of plug 10 if desired by the patient, orit can be shorter (see FIG. 7) and serve only to protect the plug fromapplicator puncture or stiffen stem portion 12 to improve the seal inthe high pressure zone of the anal canal.

Insert 23 can also be used to facilitate an applicator-free positioningas is further described hereinbelow.

Experiments conducted by the present inventors have determined that aplug of the geometry in FIG. 7 was slightly uncomfortable when made ofsilicone of Shore A 40 or harder, but essentially unnoticeable when madeof a silicone of Shore A 3. Therefore, in order to be comfortable andhence usable, plug 10 is constructed having minimal surface hardnessrequired to maintain its basic shape and maximal compliance to surfaceand tissue anatomy. Such properties can be achieved by fabricating solidstructures from soft materials such as low Shore silicone (e.g. <40Shore A value), silicone-latex, open or closed cell foams (e.g. siliconeor polyurethane) or by constructing plug 10 as a partially or fullyfluid, gel or gas-filled hollow structure. Partial filling allows forthe plug surface to fold and/or invaginate and better conform to mucosalfolds. Preferably, plug 10 is also elastic such that it conforms to theshape of the anal canal during movement thus being effective in sealingwhile being compliant to tissue movement over extended time periods(hours to days). Plug 10 can also be constructed from a rigid yetpartially elastic material which is coated with a soft material such asShore A 3 silicone or constructed from a thin higher shore materialfilled with a gas, liquid, gel or comprised of a foam structure whichlowers the effective shore of the entire structure to a comfortablelevel.

Stem portion 12 is preferably elastic and flimsy so as to enable fittingof plug 10 to individuals of varying anal canal lengths. Such elasticityensures that plug 10 can be stretched and bent to accommodate analcanals of varying lengths and geometry. Preferably, stem portion 12 isfabricated with variable elasticity along its length such that a lowerregion of stem portion 12 stretches more than an upper region (adjacentto cap portion 14) when plug 10 is fitted.

For example, stem portion 12 can be fabricated such that a lower regionthereof is elastic and thus stretchable while an upper region is lesselastic (or even rigid) and thus less stretchable. Such a configurationensures that plug 10 can accommodate various anal canal lengths bystretching at a lower region thereof and not an upper region. Enablingplug 10 length accommodation without stretching or distorting an upperregion of stem portion 12 as well as cap portion 14 attached thereto,ensures that the sealing function of stem upper region 13 against thehigh pressure zone of the anal canal and cap portion 14 are maintained.

An example of a stem portion 12 having such variable elasticity is shownin FIG. 6B. In this configuration, an internal sleeve 23 which runs thelength of stem portion 12 is attached to upper region 13 and not lowerregion 19 of stem portion 12. Thus, stem portion 12 is capable ofappreciably stretching at lower region 19 and the configuration of upperregion 13 and cap portion 14 are maintained and their sealing functionsremain unchanged regardless of the length of anal canal to which plug 10is fitted.

Anal canal length ranges from about 2-5 cm (Morren G. L., BritishJournal of Surgery, 2001, 88, 1506-1512 and Gold, D. M., British Journalof Surgery, 1999, 86, 365-370). Thus, lower region 19 is configured toelastically stretch so as to accommodate such variance in canal lengthwithout affecting the diameter and shape of upper region 13 and capportion 14. Any friction between lower region 19 and internal sleeve 23or the inner sleeve and the applicator can be reduced via use of variouslubricants (e.g. talc, paraffin, glycerin, PEG, mineral oil and thelike).

FIG. 7 is a cut-away cross-section of one configuration of the plug ofthe present invention. This Figure illustrates nose cone 16 whichfacilitates delivery, soft upper disk 15 of cap portion 14 which isconfigured for sealing at bottom of rectum, and the cylindrical seal ofthe upper region 13 which rests against the anal canal high pressurezone of stem portion 12. Also illustrated is the thin highly-elasticlower region 19 of stem portion 12 that stretches to accommodatevariable lengths of anal canals and allows overshoot upon pluginsertion. Lower region 19 of stem portion 12 is 0.4 mm thick and has across sectional surface area of around 1 sq mm to enable high elasticityand deformations with low forces. Biasing cap 21 rests outside the anusto retain plug 10 in position, while insert 23 is made of hardersilicone and provides more stiffness to upper region 13 of stem portion12 in order to prevent applicator perforation of plug 10.

Plug 10, or portions/layers thereof, can be made of a hydrophobicmaterial, in which case an open-cell foam will allow for gas to ventthrough the plug without the passage of liquid or solid fecal matter, ora hydrophilic material, in which case a closed cell foam would bepreferable. In general, a hydrophobic material is preferable to minimizeseepage of liquid between the tissue and plug surface.

In a further embodiment, plug 10 or portions thereof are made of abiodegradable material that can be flushed down the toilet and degradenaturally in the waste water. Such water degradation properties canoccur over weeks or months, but not affect the ability of Plug 10 tofunction and withstand the humid environment of the rectum for hours oreven days. Example materials include collagen, gelatin, gum, agarose,hydrogels, materials used in denture adhesive, or the like.

Dissolution of the biodegradable material comprising plug 10 or portionsthereof can proceed from the surface. The dissolved polymers can form atight seal by fitting within the smallest of mucosal folds, as long asthe viscosity of the dissolved polymer is sufficiently high andlubrication is controlled. Other biodegradable materials includederivatized cellulosics, for example hydroxy methyl cellulose orpolyvinyl alcohol. Such materials can be formulated in a hydrogel,hydrated and cross-linked or alternatively in a non-hydrogel, desiccatedor non-crosslinked state (with appropriate moisture control packaging).Additionally, biodegradable or hydrolysable polymers can be made to haveslow degradation times and generally degrade by bulk hydrolyticmechanisms. Such materials include as polylactic or glycol acids.Typical degradation times would be in weeks, over which time suchmaterial would lose its mechanical properties. Other degradablematerials include certain polycarbonates or polyanhydrides, polymers andcopolymers of phthalic acid, isophthalic acid with compounds likecaprolactone or valerolactone, maleic anhydride or phthalic anhydrideand the like. All materials listed above can be made in a softformulation. Plug 10 can be made of combinations of biodegradablematerials. For example inner sleeve 23 can be a hard plastic such aspolylactic acid (PLA) encased in a softer gelatin or cellulosic outerplug.

Plug 10 or portions thereof can be fabricated by a compound thatsoftens, plasticizes or even molds itself under humid conditions, atbody temperature or under other conditions present or caused during plug10 insertion, thereby increasing compliance to the natural tissueanatomy.

Plug 10 or portions thereof can be made of a solid core with a gel,liquid or gas filled blistered surface that allows for adequate surfaceconformation/invagination with the solid core provides structuralrigidity.

Plug 10 can also be coated with a gel or gelling material (e.g.desiccated hydrogel). Such coating can provide additional surfaceimpressibility (conformity to surface anatomy, e.g. folds of anal canalwall), better sealing and adhesion for improved anchoring and resistanceto plug migration.

Plug 10 can also be filled with gel or fluid that exudes out of pores ofthe plug body to improve sealing.

Plug 10 can also be fabricated from an inelastic core which isovermolded with elastic soft material. For example, hydrated ordehydrated gelatin, agarose or other deformable, elastic or moldablepolymer or hydrogel can be overmolded on an axially inelastic backbone,such as a string or collapsible tube (with insert).

For example, plug 10 can be dry coated with a layer of desiccatedcarboxymethyl cellulose which upon contact with anal and/or rectaltissue hydrates into a gel layer which follows the microscopic andmacroscopic contours of the tissue folds. It will be appreciated thatplug 10 coated with a hydrogel can be fabricated from a higher shorematerial since such a coating can provide the necessary compliance withtissue surface morphology.

Plug 10 or portions thereof can be coated with a high viscosityhydrophobic agent that might soften but does not flow at bodytemperature, such as various forms of grease or wax, to help preventleakage of liquid fecal matter.

As is mentioned above, cap portion 14 is designed to seal at the rectalneck region at the top of the anal canal. Since the rectum is angledback with respect to the anal canal (see FIG. 2), plug 10 design musttake into consideration this angulation and the effect of rectal tissuemovement (e.g. radial expansion and forward distension of the rectumwall during rectal filling with fecal matter) on cap portion 14.Furthermore, this angulation changes from patient to patient and changesdynamically during the filling of the rectum for any given patient.

As is known in the art and as is evident by the shape of the VPS plugsused in the experiments underlying the present invention, the rearwardangulation of the anal canal for patients with fecal incontinence isless than in normal patients. Restoration of this angle is normallyaccomplished only through surgical repair. In a further embodiment, plug10 can be pre-curved and act as a semi-rigid internal armature thatrestores the appropriate puborectalis angle that will help restore apatient's continence. This effect can be in addition to or instead ofthe sealing effect of plug 10.

During rectal filling, the rectal canal widens to accommodate fecalmatter. Such widening displaces opposing rectal walls and altersangulation between the anal canal and the rectum. In addition, fecalmatter entering the rectum pushes down on the top of the anal canalregion. A cap portion 14 which is not well seated in this region orcontacts the walls of the rectum will be pushed aside (‘peeled’) by thefecal matter. In such cases, a seal created by cap portion 14 can becompromised by the pressure of fecal solids and liquids migrating aroundcap portion 14 and into the anal canal. In order to prevent suchdisplacement, cap portion 14 is designed so as to deform elastically toconform to the change of rectum geometry or to occupy a minimalfootprint across the tissue above the anal canal ensuring that pressurefrom fecal matter along the walls does not displace it from its positionor leak around the plug and into the anal canal. However, too small orsoft of a cap portion 14 will allow migration of plug 10 down into theanal canal and the premature loss of plug 10. Lessons learned from thein-situ formed VPS plug of FIG. 2 suggest that the region above the analcanal can be effectively sealed by using a cap structure approximately1-5 cm in diameter and that a cap having a low profile (e.g. flat disc,inverted cone) would not be displaced by feces. It will be appreciatedthat although the stem-cap configurations described above is presentlypreferred, configurations in which the stem portion is considerablyshorter (e.g. 0.5-2 cm) or configurations which only include the stemportion or the cap portions separately are also envisaged. In a furtherembodiment, the cap portion can be connected to a fine elastic stemwhich itself is anchored to a biasing cap element that remains outsidethe anal canal between the legs of the subject. The very small diameterstem, shaped like a rubber band or elastic string, acts as an elastictether between the cap portion and the external biasing cap therebyapplying a predetermined force on the cap portion against the neckregion of the lower rectum.

Plug 10 of the present invention, if made with an open top portion 14,can be used for stool sample collection. Fecal matter will be impactedinto hollow stem portion 12, and then removed by pulling on biasingelement 21 and sent for analysis without the patient needing to touchany fecal matter.

Plug 10 of the present invention can also be used to provide electricalstimulation to anal canal and rectal tissues. A plug 10 provided withelectrodes and a power supply as well as circuitry and a controller canbe used to deliver controllable electrical pulses to the wall of theanal canal and/or lower rectum for the purpose of stimulating,contracting and/or biofeedback training sphincter muscles surroundingthese tissues. Power to plug 10 can be provided in the form of a batteryor capacitor positioned within the plug or a coil which is positionedwithin the plug and activated via remote induction. A controller, whichcan either be positioned within the plug or within a remote device canbe used to provide commands according to sensor data (from sensorpositioned on the plug or elsewhere). Such stimulation to causesphincter contraction, for example, can be activated only when a sensorsenses fecal material in the rectum and/or a loosening of the analsphincters.

Plug 10 of the present invention is preferably delivered using adedicated applicator. FIGS. 4A-C and 8A-C illustrate delivery of plug 10using such an applicator which is referred to herein as applicator 50 orapplicator 100.

In the embodiment shown in FIG. 4A-C, applicator 50 is designed as ahollow tube and is sized for insertion into the anal canal.

Plug 10 is pre-loaded into a bore 52 of applicator 50 with cap portion14 protruding from applicator tip 54 (FIG. 4A and FIG. 5C). Uponinsertion into the anal canal, cap portion 14 (shaped as a conical,cup-shaped structure in this example) is either inserted as is anddeformed due to its softness, folded forward in applicator 50 or foldedback against the outside surface of applicator 50. To this end, thesurface of cap portion 14 can be pre-coated with a lubricant (e.g. aloevera, paraffin, Vaseline™, Astroglide™ or KY™ gel) in order tofacilitate insertion into the anal canal. Alternatively, cap portion 14can be folded forward and held in place with film that dissolves inliquid to avoid the need to overshoot the lower rectum duringintroduction of plug 10. Applicator 50 is pushed with handle 53 (FIG.5B) into a depth determined by a stop 56 at the base of applicator 50such that it spans the anal canal with applicator tip 54 residing withinthe rectum and cap portion 14 assuming the position shown in FIG. 4Babove the top edge of the anal canal. Applicator 50 is optionallyfabricated as an elastic structure so it can follow the angulation ofthe anal canal-rectum passageway or it can be curved to allow for betterconformance to the curved anal canal during insertion.

Once in position, applicator 50 is pulled back such that cap portion 14contacts the narrowed neck region above the anal canal; the force of theneck region on cap portion 14 releases stem portion 12 of plug 10 fromapplicator 50, thereby positioning plug 10 following removal ofapplicator 50 (FIG. 4C). In order to ensure that plug 10 does notrelease from applicator prematurely or that it does not release if notin the correct position, bore 52 of applicator 50 can include amechanism 58 which engages stem portion 12 of plug 10 and does not allowrelease until plug 10 is correctly positioned. Such a mechanism can behand actuated or it can respond to a predetermined pulling force belowwhich release does not occur. Applicator 50 can have a concavebowl-shaped forward tip to better support and directionally-stabilizecap portion 14 during entry into the anal canal. FIGS. 5A-C illustratesone preferred plug and applicator design.

An applicator can also be configured as an internal applicator which canfit within a hollow stem portion 12, or run alongside stem portion 12.

The left side of FIG. 6B illustrates a system which includes plug 10fitted with an internal sleeve 23 and an internal applicator 100 whichis designed to engage an internal bore of internal sleeve 23.

This configuration of applicator 100 includes a finger hold 102 which isdesigned to be fitted over a fingertip (e.g. index finger) and a rod 104which is attached to finger hold 102 and is designed for fitting withinsleeve 23 of plug 10 (FIGS. 6A-B). In that respect, rod 104 can be anyshape and dimension suitable for insertion into sleeve 23. Preferablyrod 104 is cylindrical in shape and is either hollow or solid inconstruction. Rod 104 is typically 1-10 cm in length and 0.1-5 mm indiameter. Applicator 100 can be constructed from a polymer such aspolypropylene, polycarbonate, acetal, polybutylene terephtalate,polylactic acid or similar using known molding techniques and be eitherdisposable or reusable.

Finger hold 102 of applicator 100 can be designed to accommodate anyfinger size by providing an adjustment (spring-loaded) tab within thefinger-engaging portion. The diameter of the index finger first jointranges between 1.5-2.3 cm for most individuals and thus a single designcan be used to accommodate such a finger size range. An index fingerapplication is preferred since this finger is the most developed withrespect to kinesthetic feedback (proprioception), and thus most everyonecan use this finger to guide plug 10 to the anal orifice.

As is mentioned hereinabove, sleeve 23 serves two functions, to preventrod 104 from puncturing through plug 10 (and potentially damaging analmucosa or rectal tissue) and to provide upper region 13 of stem portion12 with the rigidity necessary to maintain its configuration even whenplug 10 is stretched to accommodate anal canals of varying lengths.

FIG. 8A-C illustrates plug 10 administration using applicator 100. InFIG. 8A, plug 10 is positioned over an illustration of the anal canal toindicate plug position with respect to the canal at every stage ofinsertion. Plug 10 is mounted on rod 104 of applicator 100. Due to itsflimsiness, cap portion 14 folds backwards axially to reduce the crosssectional area of cap portion 14 during insertion in the anal canal.Lubrication of the top surface of cap portion 14 can be used to easeinsertion. As shown in FIG. 8B, finger hold 12 is maneuvered to theentrance to the anus, thereby stretching stem portion 12 so that ittouches finger hold 102. Disk 15 is lifted above the lower surface ofthe rectum. As shown in FIG. 8C, when applicator 100 is removed, disk 15and stem portion 12 can return to their original shape due to inherentelasticity or some other shape-retention mechanism. The inner surface ofinternal sleeve 23 of plug 10 and applicator 100 and/or portions thereofcan also be pre-lubricated for easier removal of applicator 100following insertion of plug 10. Suitable lubricants include glycerin,polyethylene glycol, mineral oil and the like. A detent that provides aknown friction against a ball feature at the tip of rod 104 can beprovided within internal sleeve 23 in order to prevent plug 10 fromfalling off applicator 100 when held upside down. Such a detent can beconfigured such that the force applied thereby is low enough to stillrelease when applicator 100 is removed following insertion of plug 10into the anus. Experiments conducted by the inventors indicate that aretentive force of between 5 to 30 grams is ideal. It will beappreciated that following removal of applicator 100 from plug, the bareapplicator rod may be harmful if reused to position the plug. Thus, toprevent reuse of applicator 100, the rod portion thereof can befabricated from two or more lengthwise sections that split (curl out)once removed from stem portion 12. By splitting the rod of applicator100 into smaller and sideward projecting rods, reuse is prevented.Alternatively, sleeve 23 can have within it a spring loaded tab thatallows for applicator rod 104 to slide out but not re-enter internalsleeve 23, thereby also preventing reuse of plug 10. Another alternativeconfiguration can also include a rod 104 that is pivotally attached at abase portion thereof to finger hold 102 and a sleeve 23 (of plug 10)which includes a lock ring at a lower portion thereof. The lock ringlocks the pivot when plug 10 is positioned over rod 104 thus providingrod 104 with the rigidity necessary to allow plug insertion. However,when applicator 100 is removed from plug 10, rod 104 is no longerstabilized by the lock ring of sleeve 23 and thus it lacks the rigiditynecessary for reinsertion into sleeve 23 or the anal canal.

Applicators 50 or 100 can include a mechanism that is sensitive to thepressing of finger hold 102 up against the external opening of the anus,and thereby providing the user tactical or auditory feedback of properinsertion position. For example, a click can be heard when applicator 50or 100 is exposed to sufficient pressure from the front or the sides.Such pressure may also serves to collapse or otherwise disable rod 104to prevent reuse and/or release plug 10 from applicator 50 or 100 andtells the user that applicator 50 or 100 is in far enough and that itcan be withdrawn. Alternative feedback mechanisms can include a fluidfilled balloon that is disposed between applicator 100 and plug 10 andemits a sound when exposed to pressure of a predetermined threshold.Tactile feedback can be provided by using a finger hold 102 design whichfacilitates tactile feedback. For example, finger hold 104 can includean exposed or thin membrane-covered window which transmits sensation tothe operating finger such that the user can feel when plug 10 is fullyinserted. Alternatively, finger hold 102 can be provided with elements(e.g. rubber rods) that project through the surface of finger hold 102and can transmit tactile feedback from the exterior surface of fingerhold 102 to the finger of the user.

Applicators 50 or 100 can be single use applicators and be fabricatedfrom a biodegradable material (see example materials elsewhere herein)which can be recycled, safely landfilled or even flushed down thetoilet.

Applicators 50 or 100 can include a reservoir for containing a gel,fluid or gas which can be pumped into plug 10 during or after insertioninto the rectum, either manually or by pre-stored energy source.

Applicator 100 should have the ability to bend to accommodate thecurvature of the anal canal, but yet stiff enough to not buckle or bendduring the initial insertion procedure. The optimal stiffness based onexperiments done by the inventors provides stiffness range of theapplicator rod 104 so that when a preferably 50 to 250 gram weight, ormore preferably 150-200 gram weight is applied to the end of a 50 mmlong applicator rod 104, there is a tip displacement of around 10 mm.

For example, plug 10 designed as a collapsed balloon can be positionedvia applicators 50 or 100 and inflated inside the rectum with fluid,gas, particles or a gel, including a reverse thermal gelation (RTG) gelsuch as Pluronic™ that will retain their shape at body temperature, or ahardening moldable compound such as VPS.

Plug 10 when filled with a fluid, gas, particles or gel can beconfigured so as to enable transfer of the filling material betweenregions of plug 10 which are then maintained in the proper internalgeometry during movement of the anal canal and rectum. Optionally, plug10 has within it one or more one way valves that prevent transferredfluid, gel or gas from moving backwards and deflating the acquiredshape. Applicators 50 or 100 and plug 10 form a part of a system whichis preferably co-packaged as a fecal incontinence kit. The kit caninclude a reusable applicator and several disposable plugs or it caninclude disposable applicator-plug pairs as well as instructions foruse. The kit can contain a specific size of plug 10 and/or applicator 50(e.g. small, medium or large) or it can include an assortment of sizes.Such a kit can include a disposal bag and/or a moist wipe or disposablegloves to help keep the plug insertion process as hygienic as possibleeven if not performed at home.

In an additional embodiment, an applicator which is designed forattaching to biasing cap 21 can be used with a plug 10 configurationwhich can be inserted into the anal canal without use of an inner orouter rod-type applicators such as those described above (applicators 50and 100).

In such cases, plug 10 can include elements for stiffening stem portion12 to thereby enable stem portion to be rigid enough for self insertion.It will be appreciated that such configurations can also be insertedinto the anal canal without use of any applicator simply by holding plug10 at biasing cap 21 and pushing it into the anal canal.

Several configurations for stiffening stem portion 12 are envisagedherein. Stem portion 12 can be a hollow tube which is filled with a gas,liquid or gel which stiffens stem portion 12. Following insertion intothe anal canal, the gas, liquid or gel can be released from stem portion12 allowing it to conform to anal canal anatomy and stretch toaccommodate anal canal length.

A phase change material can also be used in stem portion 12 andoptionally cap portion 14; the material can be stiff under roomtemperature and soft at body temperature. Plug 100 can be filled withsuch a material and deformed while molten (e.g. by stretching the plugfrom its ends) to as to form a more deliverable structure with reducedcap portion diameter when the material sets. Once in the body, thematerial melts and plug 100 assumes its natural configuration providingthe anchoring and sealing necessary for treating fecal incontinence.

An example configuration of such a plug is shown in FIGS. 9A-B. Externalshell 19 is made of 0.4 mm thick silicone shore A 40 filled with moltenWitespol™ hard fat. The plug is stretched and allowed to cool and hardenwhile elongated as shown in FIG. 9A, thereby minimizing the crosssectional area of the plug to ease insertion and to allow disk 15 of capportion 14 of the anchoring cap to sit above the top of the anal canal.Note that disk 15 is wavy and cap portion 14 elongated when the core ofplug 10 is solid, thereby minimizing their diameters. The packaging ofthe plug can include a mechanism to keep the plug elongated duringtransport so even if the plug is exposed to temperatures above 37 degC., when the plug re-cools it will maintain its elongated shape. Muchlike a candle design, stem portion 12 can include a central wick or meshthat helps provide stiffness and resistance to breakage of a hard andotherwise delicate thin elongated wax element.

The user pushes the plug in using a finger placed in the bottom ofbiasing element 21, much like a suppository is inserted into the anus.With this design, no applicator is needed. Biasing element 21 alsoshields the user's finger from touching the entrance to the anus.Shortly after insertion into the anus, the self-contained fillingmaterial melts and the plug resumes its relaxed shape, shown in FIG. 9Bwhich allows disk 15 of cap portion 14 to seat properly in the lowerrectum. Given that the plug is made of a liquid interior, the externalshell can be made of relatively hard silicone, shore A 40+, and theoverall plug is still well tolerated by the patient due to its squishynature.

Example materials used to fill such a phase change plug include 70%poloxamer 188 (P188) and 30% propylene glycol, paraffin wax, polyesterwax, solid fats such as polyglycerol ester of fatty acids (PGEFs forexample: decaglycerol heptabehenate HB750 and hexaglycerol pentastearatePS500), beeswax, and Witepsol™ hard fats. The meltable material does notneed to come into contact with the body and can be fully sealed insideplug 10.

Plug 10 can also be positioned without use of an applicator byconfiguring plug 10 with a hydratable solid core, which softens whenhydrated. Biasing cap 21 in this embodiment is elastically connected toeither stem portion 12 or directly and independently to cap portion 14.The latter option prevents the elasticity of biasing cap 21 from beingaffected by the stiffness of stem portion 12. Stem portion 12 includes acore which is made from a hydratable material such as PVA microporousfoam or a desiccated hydrogel. Plug 10 can be elongated beyond itsnormal resting length and the rigidity of the dry core will keep it inthat state until it is hydrated, thereby making plug 10 easier to insertinto the anus. Cap portion 14 includes a top opening through whichliquids can come in contact with the foam core or a self containedliquid ampoule can be punctured during or after the insertion process tosoften the core. This opening ensures that once plug 10 is positionedwithin the anal canal, the top portion of the core wicks liquid from thelower rectal environment and into and along the length of the corethereby hydrating it and transforming it from rigid to soft. The finalsoftness and elasticity of the core when wet can be configured toprovide the proper mechanical properties that make the top portion ofstem portion 12 an effective sealing element. Plug 10 of thisconfiguration can be inserted in a manner similar to a stiff suppositoryby holding it at the bottom (biasing cap 21 region) and pushing it intothe anal canal (with cap portion 14 protruding into the lower rectum).Once positioned, the core hydrates and softens within a minute or twomaking plug 10 softer and more elastic. The liquid that hydrates thecore cannot leak out since the bottom and sides of stem portion 12 arenot permeable to liquid. Alternatively, adjacent to the core within stemportion 12 is a liquid ampoule (not shown) that is burst upon entry ofthe plug into the anal canal and thereby softens core 25 within a presettime. Such a system is fully self contained and does not rely on anyfluid transfer into or out of plug 10.

Alternatively, a coil core can also be used, in which case, compressingthe coil for insertion provides rigidity from the stacked coils,following insertion, the coil relaxes and provides the elasticitynecessary from stem portion 12. Alternatively, a stacked coil made ofpaper or a polymer can provide the necessary rigidity and be pulled out(while being unraveled) of the plug following insertion to allow for thedesired plug softness and elasticity once fully inserted. As used hereinthe term “about” refers to .+−0.10%.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination.

Additional objects, advantages, and novel features of the presentinvention will become apparent to one ordinarily skilled in the art uponexamination of the following examples, which are not intended to belimiting. Additionally, each of the various embodiments and aspects ofthe present invention as delineated hereinabove and as claimed in theclaims section below finds experimental support in the followingexample.

EXAMPLES

Reference is now made to the following example, which together with theabove description illustrate the invention in a non limiting fashion.

Example 1 Preformed Silicone Plug

A silicone plug as shaped like plug 10 in FIG. 3 having a Shore A valueof 3 was fabricated using well known silicone molding techniques. Theplug was loaded into a hollow applicator and was self administered intothe anal canal of a continent male subject (as shown in FIGS. 4A-C and5A-C). The subject carried the plug for 24 hours. Following the 24 hourperiod, the plug was ejected with defecation and collected.

Trace fecal material present on the plug indicated that feces managed tocreep under one side of the cap structure of the plug but was stopped atthe neck region of the plug (just under the cap). The stem was free offecal matter indicating that the tightest seal occurs on the stem justbelow the cap.

The subject reported that the plug did not induce any perceiveddiscomfort and remained in position throughout the experiment. Thesubject also reported that flatulence escaped around the plug withoutinducing any resistance to gas release or perceivable dislocation of theplug or leakage.

Example 2 Silicone Plug with Biasing Cap

The plug design similar to that shown in FIG. 7 made of silicone shore A3 and inner sleeve insert made from silicone shore A 20 was tested on afemale patient diagnosed with severe fecal incontinence (Wexner orCleveland Clinic Fecal Incontinence scale of 20 out of 20). On a dailybasis over the course of two weeks the plug was self administered by thesubject into the anal canal (in the manner shown in FIGS. 8A-C). Thesubject carried each plug for .about.12-24 hours over which time shealso wore incontinence pads in order to trap any leaked solids orliquids. Following each bowel movement with occurred roughly every 12-24hours, the pads and the plug were collected and analyzed (see FIG.10A-B). The pads showed no signs of soiling or leakage indicating thatthe plug effectively prevented involuntary loss of fecal matter andhence restored full continence to this subject. In addition, the top ofthe cap portion showed evidence of staining with fecal matter while plugportions below the top surface of the cap portion were free of fecalmatter as per the intended design of the plug. The subject reported thatthe plugs were very comfortable to the point of being imperceptible andwere evacuated naturally, painlessly and effortlessly. Furthermore, thesubject reported 1 to 2 normal and fuller bowel movements a day, asopposed to 5 to 6 episodes of bowel leakage prior to using the plug.

Example 3 Meltable Core Plug

The plug design similar to that shown in FIG. 9A-B with external shell19 made of silicone shore A 40, filled through the bottom of stemportion 12 with molten Witespol.™. solid fats that melts at 37 deg C.,elongated while still molten by hanging a weight of 100 grams from it,allowed to cool and then sealed with a silicone RTV adhesive at thebottom of the stem portion 12 in order to keep the meltable corematerial fully contained in the external shell of plug 10. Plug 10 wastested on a female subject diagnosed with severe fecal incontinence(Wexner scale 20). On a daily basis over the course of a week the hollowplug was self administered by the subject into the anal canal in amanner similar to the insertion of a suppository. The subject carriedeach plug for .about.12-24 hours over which time she also woreincontinence pads in order to trap any leaked solids or liquids.Following each bowel movement with occurred roughly every 12-24 hours,the pads and the plug were collected and analyzed. The pads showed nosigns of soiling or leakage indicating that the plug effectivelyprevented involuntary loss of fecal matter and hence restored fullcontinence to this subject. In addition, the top of cap portion 14showed evidence of staining with fecal matter while plug portions belowthe top surface of the cap portion were free of fecal matter as per theintended design of the plug. The plug as ejected with the core materialin a liquid state due to the plug being exposed to body temperature. Thesubject reported that the plugs were very comfortable to the point ofbeing imperceptible and were evacuated naturally, painlessly andeffortlessly. Furthermore, the subject reported 1 to 2 normal and fullerbowel movements a day, as opposed to 5 or 6 episodes of bowel leakageprior to using the plug.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims. All publications, patents and patentapplications mentioned in this specification are herein incorporated intheir entirety by reference into the specification, to the same extentas if each individual publication, patent or patent application wasspecifically and individually indicated to be incorporated herein byreference. In addition, citation or identification of any reference inthis application shall not be construed as an admission that suchreference is available as prior art to the present invention.

What is claimed is:
 1. A plug for placement in an anal canal comprising:a stem; an anchoring element at a distal end of said stem; a biasingelement at a proximal end of said stem; wherein said stem elasticallystretches to bias said anchoring element downward against a rectal neckbottom when said biasing element engages an external anal surface. 2.The plug of claim 1, wherein said stem elastically stretches toaccommodate anal canals of varying lengths while biasing said anchoringelement downward against said rectal neck bottom.
 3. The plug of claim2, wherein said stem elastically stretches to accommodate anal canallengths of 2-5 cm.
 4. The plug of claim 1, wherein said anchoringelement is disc shaped.
 5. The plug of claim 4, wherein said disc has adiameter of 2-3 cm.
 6. The plug of claim 1, wherein said biasing elementis disc shaped.
 7. The plug of claim 1, wherein said anchoring elementis configured to deform to a shape of the rectal neck bottom when biaseddownward against said rectal neck bottom.
 8. The plug of claim 7,wherein said anchoring element is disc shaped and deforms to a concaveup configuration when biased downward against said rectal neck bottom.9. The plug of claim 1, wherein an outer diameter of said stem isgreater at said distal end than said proximal end.